The invention relates to an electric motor, comprising a stator, a motor shaft, and a rotor having a rotor body with a central bore, mounted on the motor shaft. The bore wall has an elastic layer which connects the rotor body to the motor shaft.
A d.c. motor of the above type is disclosed in German Auslegeschrift No. 2,328,886 and comprises a rotor body constituted by a permanent magnet. An axially directed layer of an elastic material in the form of a sleeve is arranged between the rotor body and the motor shaft to mount the rotor body elastically on the motor shaft. During operation, the elastic layer serves to absorb a part of the kinetic energy of the rotating rotor body when the rotor is suddenly braked, in order to reduce the load exerted on a gear wheel which is coupled to the motor shaft.
A disadvantage of this known electric motor is that elastic construction only performs a function when the rotor is suddenly braked. Another disadvantage is that the elastic layer is comparatively thick and therefore readily deformable in the axial direction, so that the fixation of the rotor on the motor shaft is not rigid in this direction, which may lead to impermissably large axial displacements of the rotor body relative to the rotor shaft.